Duplicating method employing simultaneous application of electric field and exposure to radiation



United States Patent Warren G. Van Dorn;

Thomas M. Greeno, Columbus, Ohio; Vsevolod S. Mihailov, Rochester, N.Y. [21] Appl. No. 633,917

[22] Filed Apr. 26, 1967 [45] Patented Dec. 22, 1970 [73] Assignee Xerox Corporation,

Rochester, N.Y.,

a corporation of New York [72] Inventors [54] DUPLICATING METHOD EMPLOYING SIMULTANEOUS APPLICATION OF ELECTRIC FIELD AND EXPOSURE TO RADIATION 12 Claims, 5 Drawing Figs.

[52] US. Cl 101/471, 101/131,101/426, 101/469 [51] Int. Cl B4lm 5/00 [50] FieldolSearch 101/1282, 128.3,450-473,132.5,131,426;96/1,1.5,1.8, 1.3, 1.4

[56] References Cited UNITED STATES PATENTS 2,959,481 11/1960 Kucera 96/1 3,106,155 10/1963 Eastmanetal. 101/464 3,155,503 ll/l964 Cassiersetal. 96/1 Pn'mary Examiner-Edgar S. Burr Attorney-James J. Ralabate ABSTRACT: A method of preparing a highly versatile duplicating master. A photoresponsive imaging composition is interpositioned between a dual elect.ode system. Upon selective illumination of the photoresponsive material and separation of each electrode the photoresponsive composition fractures along the lines defined by the light pattern to which it has been exposed with complimentary images being formed on the surface of each electrode. The resulting imaged surface may then be used as a printing master in various modes such as a pressure transfer master, a spirit duplicating master, or as a hectograph master.

PATENTEUnEcezmm 3548748 FIG. 2

a A TTO/PNEVS DUPLICATING METHOD EMPLOYING SIMULTANEOUS APPLICATION OF ELECTRIC FIELD AND EXPOSURE TO RADIATION BACKGROUND OF THE INVENTION This invention relates to a printing system and, more specifically, to a multiple duplicating system.

in the art of duplicating, various techniques have been developed for making duplicating masters to provide multiple copies of original documents. One of the more classicalknown of these techniques is the production of carbon copies in a typewriter. Aside from the limited number of legible copies that may be produced, this technique is burdened with several inherent deficiencies. For example, the texture of the paper used in making copies must generally be extremely lightweight in order to transmit pressure for at least 2 or 3 copies. In addition, in the event that more than a couple of copies are desired, it is necessary to exert extremely high pressures on the type characters resulting in the embossment of the original. Moreover, the readability of the carbon copies drops off with each additional reproduction.

In order to overcome the many difficulties inherent in the production of duplicates with carbon paper, a number of duplicating techniques utilizing variously formed printing masters have been developed such as spirit duplicating, adherography, and thermography. A spirit duplicating process is a method whereby a master is prepared by typing or writing, resulting in the transferral of a waxlike material to the surface of a master sheet. A duplicating machine moistens the waxlike image with a spirit solvent as it presses it against the surface of a copy paper, thereby transferring a duplicate of the original image thereto. Adherography is a method of duplicating whereby copy material in the form of an image will selectively absorb infrared radiation. Heat is radiated in the image areas of the original document thereby producing a selective softening of an underlying transfer sheet containing a volatile transfer material and permitting transfer of the volatile or otherwise tacky material to a copy sheet in an imagewise configuration. It is then generally necessary to develop the transfer image with a dry powder. Thermography is a copying process wherein a special heat sensitive paper is sandwiched in between an original and a copy sheet and exposed to infrared radiation. Selective absorption brings about a reaction between a component in the heat sensitive paper coating and a component in the copy sheet thereby producing a colored image.

While basically these systems have been found useful for duplicating purposes, there are inherent disadvantages to their use. Generally speaking, these techniques are prohibitive in cost if they are used to produce a relatively small number of duplications of an original. At the present time, the master copy is usually prepared by typing, printing, writing or drawing the desired material onto a sheet of master paper or by direct contact exposure using special ribbons, carbon papers, inks or other similar imaging sources. These methods of producing the masters are both tedious and time consuming, and require highly skilled personnel to produce reliable and valuable reproductions. All these factors substantially increase the cost of the respective duplicating process.

Therefore, it is an object of this invention to provide a duplicating system which will overcome the above-noted disadvantages.

It is a further object of this invention to provide a novel duplicating system.

Another object of this invention is to provide a process of using a novel printing master.

Still a further object of this invention is to provide a novel method for the preparation of a duplicating master.

Yet, still a further object of this invention is to provide a duplicating master which may be universally adapted to any one of several printing processes.

SUMMARY OF THE INVENTION The foregoing objects and others are accomplished in accordance with the present invention, generally speaking, by coating on the surface of a donor support substrate a cohesively weak photoresponsive imaging composition to form a donor sheet. The photoresponsive imaging composition may be a homogeneous layer, however, generally it comprises a photosensitive pigment dispersed in a cohesively weak insulating binder material. Preferably, the photoresponsive composition will comprise a binder matrix having dispersed therein a metal-free phthalocyanine pigment. A receiver sheet is laid down over the surface of the imaging layer. The resulting configuration forms what is generally referred to as a manifold set. The imaging layer may then be activated by treating it with a liquid activator which generally comprises a solvent such as Sohio Odorless Solvent 3440, a kerosene fraction available from Standard Oil of Ohio. The activating step may be eliminated if the photoresponsive layer retains sufficient residual solvent after having been coated on the support substrate from a solution or paste. The activating step serves a dual function of first making the top surface of the imaging layer slightly tacky and, at the same time, weakening it structurally so that it may be fractured more easily along a sharper line which defines the image to be reproduced. An electrical field is then applied across the manifold set while it is exposed in imagewise configuration to a pattern of light and shadow representative of the image to be reproduced. Upon separation of the donor substrate and receiver sheet, the imaging or photoresponsive layer fractures along the line defined by the light pattern to which it has been exposed with part of the imaging layer being transferred to the receiver sheet while the remainder is retained on the donor substrate so that a positive image is produced on one surface while a negative image is produced on the other. At least one of the donor substrate and the receiver sheet is transparent and, if desirable, both may be transparent so that exposure may take place from either side of the manifold set. Either one or both of the donor substrate and receiver sheet may be made of a conductive material, however, a manifold set may include separation electrodes on opposite sides of an insulating donor substrate and insulating receiver sheet for purposes of applying an electrical field during the imaging phase of the process. Here again, either or both of the combinations of electrode and support layer may be transparent so as to permit exposure of the imaging layer from either side of the manifold set. The resulting manifold image prepared may then be used as a printing master in several various duplicating modes as will be more fully described hereafter.

It has been determined that a manifold image generally prepared according to the above-disclosed process may be used as a duplicating master utilizing various sundry modes. For example, the resulting manifold image may be contacted with the surface of a copy sheet and pressure applied so as to transfer an imprint of the image to the surface of the selected copy sheet, such as paper. Therefore, the imaging layer serves the dual function of imparting light sensitivity to the system while at the same time acting as the colorant source of the transferred image. Other colorants such as dyes and/or pigments may be added to the photosensitive matrix so as to intensify or modify the color of the final image produced. This imaging technique by pressure transfer may be enhanced by tackifying the manifold image by any suitable means such as by exposure to a heat source, by creating a solvent vapor environment, or by the inclusion of a nonvolatile solvent in the imaging suspension thereby increasing its readiness to be transferred. lf desirable, the transferred image may be developed or its imprint enhanced by subsequent treatment with a developer material which will intensify the resulting transferred image. This is preferably accomplished while the image is in a tacky state.

Still another use of the manifold image prepared according to the process of the present invention is as a spirit duplicating master. In this instance the colorant contained in the imaging layer or otherwise used to intensify or further develop manifold image produced will be a spirit solvent soluble dye or dye composition. Copies may then be made from the manifold master by contacting the image surface with a copy sheet in the presence of an alcohol or other spirit solvent which will pick up a portion of the dye and transfer it to the copy sheet in imagewise configuration. Alternatively, the manifold image may be used as a resist or a mask in the preparation of a hectograph master by either transferring the image to the surface of a conventional hectograph master sheet or by forming the images directly on the surface of a hectograph master sheet and thereafter printing from the unmasked areas in a conventional spirit duplicating system. In a similar but different technique of using the manifold master, the image formed may contain or may be made to contain a chemically reactive ingredient which when brought into contact with a paper copy sheet, coated or impregnated with a reaction partner for the reactive agent in the presence of a selective solvent for the image containing ingredient, will react to form a reproduction of the image on the copy sheet.

DETAILED DESCRIPTION In accordance with the present invention, a donor sheet is prepared by applying a donor or imaging layer of a photoresponsive imaging composition on a donor support substrate. Although the photoresponsive imaging layer may consist of a homogeneous layer made up of a single component or a solid solution of two or more components where they exhibit the desired photoresponse and physical properties, it has been determined that the standard and generally preferred photoresponsive coating be composed of a dispersion of a photoconductive pigment in an insulating binder matrix. Optimum results are obtained with a metal-free phthalocyanine pigment dispersed in a wax binder material in the presence of a petroleumlike solvent such as petroleum ether. The coating of the donor composition is applied to a donor support substrate by any suitable means such as by flow coating or by a wire-wound coating rod, and dried either by the application of heat or in air at room temperature. The final thickness of the donor coating or imaging layer generally will be in the range of from about 0.5 to about 45 microns with maximum utility as a duplicating master being obtained at the upper extremity of the stated range. Optimum results are obtained at a thickness of from about to about 43 microns. The basic physical property desired in the imaging layer is that it be frangible, having a relatively low of cohesive strength either in the as-coated condition or after it has been suitably activated by liquid activator. The ratio of photoconductive pigment to the binder by volume in the dispersion or heterogeneous system may range from about 10 to l to about I to 10, but it has generally been found that proportions in the range from about 1 to 2 to about 2 to I produce the optimum results, and, accordingly, constitute the preferred range.

Following the application of the donor composition to the surface of the support substrate a receiving sheet is placed on the surface of the imaging layer. Each member of the donor support and receiver sheet assembly may consist of a conductive material, such as conductive cellophane, but more commonly they will consist of an insulating material mounted on a conductive electrode. In a preferred embodiment of the present invention Mylar, polyethylene terephthalate, is used as the donor sheet backed up by a conductive electrode. This electrode is generally transparent in nature, and may consist of a layer of optically transparent glass overcoated with a thin optically transparent layer of conductive material such as tin oxide. The receiving sheet, which may also be Mylar, is generally backed up by a receiver electrode which is usually an opaque electrode such as conductive black paper. However, either or both of the working electrodes may be transparent so as to permit exposure of the imaging layer from either perspective.

After the formation of the above-described configuration, the receiver sheet is lifted or the manifold set opened and an activator applied to the imaging layer following which the layers are again closed together. The activator material when necessary is usually applied in the form of a solvent-type liquid such as a petroleum ether. As stated above, the activation step may be eliminated if the photoresponsive layer is prepared in such a manner so as to retain a sufficient amount of solvent after having been coated on the support substrate or if the imaging layer is initially fabricated so as to have a low enough cohesive strength. It is generally preferred, however, to include the activation step in the imaging process in order to produce a stronger and more permanent imaging layer which can withstand storage thereby increasing shelf life and which will, in addition, provide a more permanent duplicating master following imaging.

Although when utilized the activator may be applied by any suitable technique such as with a brush, with a smooth or rough surface roller, by flow-coating, by vapor condensation or other similar techniques, a very expedient approach is to spray the activator onto the surface of the imaging layer of the manifold set. Following the application of the activator fluid, the manifold set is again closed under pressure to spread the activator and to insure the necessary surface contact between the various layers while removing any excess activator fluid which may have been deposited. The activator serves to create an adhesive bond between the imaging layer and the receiver sheet as well as to swell or otherwise weaken and thereby lower the cohesive strength of the imaging layer. It is desirable that the activator also have a high level of resistivity so that it will not provide electrically conductive paths through the imaging layer and in addition, so that the imaging layer will support the electrical field which is applied during the exposure phase of the process. Accordingly, it will generally be found to be desirable to purify commercial grades of activators so as to remove impurities which might impart a higher level of conductivity than is desired to the activating fluids. This may be accomplished by running the fluids through a clay column or by any other suitable purification technique.

Following the preparation of the imaging layer and consolidation of the manifold set, an electrical field is applied across the imaging layer as it is exposed by means of electromagnetic radiation to the image to be reproduced. Upon separation of the donor substrate from the receiving sheet, the imaging layer will fracture along the edges of the exposed areas and at the surface where it is adhered to either the donor substrate or the receiver sheet. Accordingly, once separation is complete, exposed portions of the imaging layer are retained on one of the layers while unexposed portions are retained on the other layer, thereby resulting in the simultaneous formation of a positive image on the one hand and a negative image on the other. Whether the exposed portions are retained on the donor substrate or transferred to the receiver sheet will, of course, depend upon the particular photoresponsive material employed in the imaging member as well as the polarity of the applied field. Optimum results were obtained when the positive terminal of the power supply was connected to a NESA glass donor supporting electrode and the grounded negative terminal connected to the opaque electrode.

The final image produced on the respective surfaces may then be fixed either automatically by air evaporation of the volatile components or by fixing the binder matrix by the application of heat. The final master thereby produced may be used in conjunction with any one of the above-described duplicating systems with the particular system employed being dictated by the constituents used to prepare the manifold duplicating master.

It is to be understood that any suitable photoresponsive material may be employed in the course of the present invention with the choice depending largely upon the photosensitivity required, the spectral sensitivity, the degree of contrast desired in the final image, whether a heterogeneous or a homogeneous system is desired and similar considerations.

' l Typical photoconductors include? substituted and unsubstituted phthalocyanine, quinacridortes, zinc oxide, mercuric sulfide, Algol Yellow (C.l. No. 67,300), cadmium sulfide, cad- I 'mium selenide, Indofast Brilliant Scarlet Toner (C.I. No. 71,140), zinc sulfide, selenium, antimony sulfide, mercuric oxide, indium trisulfide, titanium dioxide, arsenic sulfide, Pb O4, gallium triselenide, zinc cadmium sulfide, lead iodide, lead selenide, lead sulfide, lead telluride, lead chromate, gallium telluride, mercuric selenide, and the iodides, sulfides, selenides and tellurides of bismuth aluminum and molybdenum. Others include the more soluble organic photoconductors (which facilitate the fabrication of homogeneous systems) especially when these'are complexed with small amounts (up to about five percent) of suitable Lewis acids. Typical of these organic photoconductors are 4,5-diphenylimidazolidinone; 4,5-diphenylimidazolidinethione; 4,5- bis- (4'-amino-phenyl)- ilnidazolidlnone; 1,5-dicyanonaphthalene; 1,4- dicyanonaphthalene; aminophthalodinitrile; nitrophthalidinitrile; l ,2 ,5,6-tetraazacyclooctatetraene- (2,4,6,8 3,4-di-( 4'-methoxyphenyl)-7,S-diphenyl-l ,2,5,6-

tetraazacyclooctatetraene-(2,4,6,8); 3,4-di-(4'-phenoxyphenyl)7,8-diphenyll ,2,5,6-tetraazacyclooctatetraene-( 2,4,6,8 3 ,4,7,8-tetramethoxyl ,2,5,6-tetraazacyclooctatetraene- (2,4,6,8); 2-mercaptobenzthiazole; 2-phenyl-4-diphenylidene-oxazolone; Z-phenyl-4-p-methoxybenzlidene-oxazolone; 6-hydroxy-2-phenyl-3-( P-dimethylaminophenyl benzofurane; 6-hydroxy-.2,3-di-(p-methoxyphenyl)-benzofurane; 2,3,5,6-tetraw(p-methoxyphenyl)-furo-(3,2f)-benzofurane; 4-dimethylaminobenzylidene-benzhydrazide; 4- dimethylaminobenzylideneisonicotinic acid hydrazide; furfurylidene-(2)-4'-dimethylaminobenzhydradize; S-benzilidene-amino-acenaphthene; 3-benzylidene-amino-carbazole; (4-N,N-dimethylaminobenzylidene)-p-N,N-

demethyliainoaniline; (Z-nitrobenzylidene)fp-bromo-aniline; N,N-dimethyl-N'-(2-nitro-4-cyanobenzylidene)-p-phenylenediamine; 2,4-diphenylquinazoline; 2-(4'aminophenyl)-4- phenylquinazoline; 2-phenyl-4-(4'-dimethylaminophenyl)-7- methoxyquinazoline; l,3-diphenyltetrahydroimidazole; 1,3-

di-( 4-chlorophenyl)-tetrahydroimidazole; l ,3-diphenyl-2- 4'-dimethylaminophenyl)-tetrahydroimidazole; l ,3-di-(ptolyl)-2-[quinovyl-(2'-)l-tetrahydromidazole; -bis[4- aminophenyl-( l )]-bis[4'-(N-ethyl-N-acetylamino)-phenyl (l)]3-(4'-dimethylaminophenyl)-5-(4' methoxyphenyl--phenyl-l ,2,4 -triazine; 3 -pyridil-(4' )-5-(4' dimethylaminophenyl)-6-phenyl-l ,2,4-triazine; 3,(4'- aminophenyl)-5,6-diphenyl-l ,2,4-triazine; 2,5-bis[4'- aminophenyl-( l ')]-1,3,4-triazole; 2,5-bis[4'(N-ethyl-N- acetylamino )-amino )-phenyl-( l )]-triazole; l,S-diphenyl-3- methylpyrazoline; l,3,4,5-tetraphenylpyrazoline; 1-methyl-2- 3 '4 '-dihydroxy-methylene-phenyl )-benzimid azole; 2-( 4'- dimethylaminophenyU-bcnzoxazole; 2- (4-methoxyphenyl)- benzthiazole; 2,5-bis-[p-aminophenyl-( l l ,3,4-oxidiazole; 4,5-diphenylimidazolone; B-aminocarbazole; copolymers and mixtures thereof. Any suitable Lewis acid (electron acceptor) may be employed under complexing conditions with many of oxir dolefildehyde"pyridine-2,6-dialdehyde, biphenyl-4-aldehyde; organic phosphonic acid such as 4-chloro-3-nitrobenzene-phosphonic acid; nitrophenols, such as 4-nitrophenol and picric acid; acid anhydrides, for example, acetic-anhydride, succinic anhydride, maleic arihydride, phthalic anhydride, tetrachloro-phthalic anhydride, perylene 3,49,10- tetracarboxylic acid and chrysens 2,3,8,9-tetracarboxylic acid anhydride, di-bromo maleicacid anhydride; metal-halides of the metals and metalloids of the groups lB-VllB, lIA-VA and group VIII of the periodical system, for example: aluminum chloride, zinc chloride, ferric chloride, tin tetrachloride (stannic chloride), arsenic trichloride, stannous chloride, antimony pentachloride, magnesium chloride, magnesium bromide, calcium bromide, calcium iodide, strontium bromide, chromic bromide, manganous chloride, cobaltous chloride, cobaltic chloride, cupric bromide; ceric chloride, thorium chloride, arsenic tri-iodide, boron halide compounds, for example: boron trifluoride and boron trichloride; and ketones, such as acetophenone, benzophenone, 2-acetylnaphthalene, benzil, benzoin, 5-benzoyl acenaphthene, biacene-dione, 9-acetylanthracene, 9-benzoylanthracene, 4- (4-dimethylaminocinnamoyl)- l -acetylbenzene, acetoacetic acid anilide, indandione-( 1,3),-( l-3-diketohydrindene), acenaphthene quinonedichloride, anisil, 2,2-pyridil, furil; mineral acids such as the hydrogen halides, sulfuric acid and phosphoric acid; organic carboxylic acids, such as acetic acid and the substitution products thereof such as monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, phenylacetic acid, and 6-methylcoumarinylacetic acid (4), maleic acid, cinnarnic acid, benzoic acid, l-(4-diethylamino-benzoyl)-benzene-2-carboxylic acid, phthalic acid, and tetrachlorophthalic acid, alpha-beta-dibromo-beta-formylacrylic acid (mucobromic acid), dibromomaleic acid, 2- bromo-benzoic acid, gallic acid, 3-nitro-2-hydroxyl-l-benzoic acid, 2-nitro phenoxyacetic acid, 2-nitrobenzoic acid, 3- nitrobenzoic acid, 4-nitrobenzoic acid, 3-nitro-4-ethoxybenzoic acid, 2-chloro-4-nitro-1-benzoic acid, 2-chloro-4- nitro-l-benzoic acid, 3-nitro-4-methoxybenzoic acid, 4-nitro-l l-methylbenzoic acid, 2-chloro5-nitro1 -l-benzoic acid, 3- chloro-6-nitrol -benzoic acid, 4-chloro-3-nitrol -benzoic acid, 5-chloro-3-nitro-2-hydroxybenzoic acid, 4-chloro-2- hydroxybenzoic acid, 2,4dinitro-l-benzoic acid, 2-bromo-5- nitrobenzoic acid, 4-chloro-phenyl acetic acid, Z-chlorocinnamic acid, Z-cyanocinnamic acid, 2,4-dichlorobenzoic acid, 3,5-dinitro-benzoic acid, 3,5-dinitrosalycylic acid, malonic acid, mucic acid, aceto-salycylic acid, benzilic acid, butanetetracarboxylic acid, citric acid; cyanoacetic acid, cyclohexanedicarboxylic acid, cyclohexanecarboxylic acid, 9,10-dichlorostearic acid, fumaric acid, itaconic acid, lev u linic acid (levulic acid); malic acid, succinic acid, alphabromostearic acid, citraconic acid, dibromosuccinic acid, pyrene-2,3,7,8-tetracarboxylic acid, tartaric acid, organic sulfonic acid, such as 4-toluene sulfonic acid, and benzene sulfonic acid, 2,4-dinitro-l-methyl-benzene-6-sulfonic acid, 2,6- dinitro-l-hydroxybenzene-4-sulfonic acid and mixtures thereof.

In addition, other photoconductors may be formed by complexing one or more suitable Lewis acids with polymers which are ordinarily not thought of as photoconductors. Typical polymers which may be complexed in this manner include the following illustrative materials: polyethylene terephthalate, polyamides, polyimides, polycarbonates, polyacrylates, polymethylmethacrylates, polyvinyl fluorides, polyvinyl chlorides, polyvinyl acetates, polystyrene, styrene-butadiene copolymers, polymethacrylates, silicone resins, chlorinated rubber, and mixtures and copolymers thereof where applicable; thermosetting resins such as epoxy resins, phenoxy resins, phenolics, epoxy-phenolic copolymers, epoxy urea formaldehyde copolymers, epoxy melamine-formaldehyde copolymers and mixtures thereof, where applicable. Other typical resins are epoxy esters, vinyl epoxy resins, tall-oil modified epoxies, and mixtures thereof where applicable.

It is also to be understood in connection with the heterogeneous system that the photoconductive particles themselves may consist of any suitable one or more of the aforementioned photoconductors, either organic or inorganic,

" dispersed in, in solid solution in, or copolymerized with any generally should have a relatively low cohesive strength either in the as-coated condition or following activation. This, of course, is true for both the homogeneous systems and the heterogeneous systems. One technique for achieving low cohesive strength in the imaging layer is to employ relatively weak, low molecular weight materials therein. Thus, for example, in a single component, homogeneous layer, a monomeric compound or a low molecular weight polymer complexed with a Lewis acid to impart a high level of photosensitivity to the layer may be employed. Similarly, when a homogeneous layer utilizing two or more components in solid solution is selected to make up the donor layer either one or both of the components of the solid solution may be a low molecular weight material such that the layer has the desired low level of cohesive strength. This approach may also be taken in connection with the preparation of a heterogeneous imaging layer. Although the binder material in the heterogeneous system may in itself be photosensitive, it is not necessary that it have this property so that materials such as microcrystalline wax, parafin wax, low molecular weight polyethylene and other low molecular weight polymers may be selected for use as the binder material solely on the basis of physical properties and the fact they are insulating materials, without regard to their photoresponsiveness. This is also true of the two component homogeneous system where nonphotoresponsive materials with the desired physical properties may be used in solid solution with photoresponsive material. Any other suitable technique for achieving low cohesive strength in the imaging layer of the present system may also be employed. For example, suitable blends of incompatible materials such as a blend of a polysiloxane resin with a polyacrylic ester resin may be used either as a binder layer in a heterogeneous system or in conjunction with a homogeneous system in which the photoresponsive material may be either one of the incompatible components complexed with a Lewis acid or a separate and additional component of the layer.

While as stated above either one or both of the donor sup port substrate and receiving sheet or substrate may be conductive in nature such as conductive cellophane the use of such flexible, transparent conductive materials for the most part will furnish a relatively weak support. Therefore, the use of an insulating donor substrate and receiver sheet backed up in each instance by a working electrode allows for the use of high strength insulating polymers such as polyethylene, polypropylene, polyethylene terephthalate (Mylar), cellulose acetate, Saran, a vinyl chlorine-vinylidene chloride copolymer and similar materials. Not only does the use of this type of high strength polymer provide a strong substrate for the manifold imagesforrned on the donor substrate and receiver sheet but in addition it provides an electrical barrier between the electrodes and the imaging layer which tends to inhibit electrical breakdown of the system. Further, structural combinations of the manifold set are more fully described in copending application Ser. No. 452,641 filed May 3, 1965 now abandoned in favor of copending application Ser. No. 708,380 filed Feb. 26, 1968 having a common assignee.

Any suitable activator agent may be employed during the course of the present invention. Generally speaking, the activator may consist of any suitable solvent having properties as set out above and which has the above-described effect on the imaging or donor layer. For purposes of this invention the term solvent" shall be understood to include not only materials which are conventionally thought of as solvents but also those which are thought of as partial solvents, swelling agents or softening agents for the imaging layer. It is generally preferred that the activator solvents have a relatively low boil ing point so that fixing of the resulting duplicating image may be accomplished by solvent evaporation,.with a very mild application of heat if necessary. It is to be understood, however, that the invention is not limited to the use of these relatively volatile activators. In fact, very high boiling point, nonvolatile activators, including silicone oils such as dimethyl polysiloxanes and very high boiling point long chain aliphatic hydrocarbon oils ordinarily used as transformer oils such as Wemco-C transformer oil, available from Westinghouse Electric Co., have also been successfully utilized in the imaging process. Generally speaking, therefore, any suitable volatile or nonvolatile solvent activator may be employed. Typical solvents include Sohio Odorless Solvent 3440, an aliphatic (kerosene) hydrocarbon fraction commercially available from Standard Oil Co. of Ohio, carbon tetrachloride, petroleum ether, Freon 214 (tetrafluorotetrachloropropane), other halogenated hydrocarbons such as chloroform, methylene chloride, trichloroethylene, perchloroethylene, chlorobenzene, trichloromonofluoro methane, tetrachloro difiuoroethane, trichlorotrifluoroethane, amides such as formamide, dirnethyl formamide, esters such as ethyl acetate, isopropyl acetate, butyl acetate, amyl acetate, cyclohexyl acetate, isobutyl propyanate and butyl lactate, ethers such as diethyl ether,

diisopropyl ether, dioxane, tetrahydrofuran, ethylene glycol monoethyl ether, aromatic and aliphatic hydrocarbons such as benzene, toluene, xylene, hexane, cyclohexane, gasoline, mineral spirits and white mineral oil, ketones such as acetone, methylethyl ketone, methyl isobutyl ketone, and cyclohexanone and vegetable oils such as coconut oil, bamboo bassu oil, palm oil, olive oil, castor oil, peanut oil, neats foot oil, and mixtures thereof.

With respect to the exposure phase of the process of the present invention an electrical field is applied across the manifold set as it is exposed to the image to be reproduced. By preparing the imaging configuration in such a manner that the initial degree of adherence of the donor layer to the donor support is only slightly higher than that of the donor layer to the receiving substrate, the imaging layer will remain on the donor support substrate unless the combined effect of exposure and applied field are added to the bond strength of the receiving sheet and the donor layer thereby exceeding the strength of the bond between the donor layer and the donor support substrate. In this way an amplification effect is achieved and transfer may be effectedwith relatively low levels of light exposure. The application of the required electrical field is relatively straightforward, generally falling within a range of from about 1,000 to about 25,000 volts per mil, with a preferred field strength in the range of from about l,500-2,000 volts per mil; however, with some materials there is a preferred polarity orientation. Thus, for example, with an imaging layer made up of finely divided metal-free phthalocyanine particles dispersed in a microcrystalline wax, it has been determined that the best images generally are formed when the illuminated electrode backing of the donor support substrate is made positive and the nonilluminated receiving sheet backing electrode negative.

A visible light source, an ultraviolet light source. or any other suitable source of actinic electromagnetic radiation may be used to expose the manifold set of the present invention.

Higher quality images are obtained by exposing from the donor side of the imaging layer, and accordingly, the receiver sheet is usually separated from the remaining layers of the manifold set just after image exposure and generally with the power still being supplied to both electrodes. However, short delays in separation after the exposure step do not appear to have deleterious effects on the images produced. Essentially the same results are obtained when separation is made after the power to the system is turned off, but, generally, the images are somewhat poorer in quality. Exposure parameters such as the magnitude of the applied potential and the like may be found in the above mentioned copending application Ser. No. 452,64l.

If a relatively volatile activator is employed, such as petroleum ether, carbon tetrachloride or Freon 2l5, fixing of the duplicating image occurs almost instantaneously inasmuch as a relatively small amount of the activator is present. With somewhat less volatile activators, such as the Sohio Odorless Solvent 3440 or Freon 214, described above, fixing may be accelerated by blowing air over the images or warming them to a temperature of about 150 F., whereas. with the even less volatile activators, such as transformer oil, fixing is accomplished by a blotting effect which may be supplied by an accessory substrate. In addition to the above disclosed fixing techniques any other suitable method may be employed which will occur to those skilled in the art.

The duplicating image produced according to the process of the present invention may be employed, as stated above, depending upon the various components of the donor layer, in one of several different modes as a duplicating master. When choosing the photoresponsive element of the imaging system the components may be so selected such that there will be formed an intensely colored image. Thus, for example, in the two-phase system, intensely colored photoresponsive pigments such as phthalocyanine blues, quinacridone reds and similar pigments may be used with the alpha and x-crystalline forms of metal-free phthalocyanine, the latter, prepared according to the process described in copending US. Pat. application Ser. No. 375,]91 filed June 15, 1964, being especially useful due to its very high sensitivity. The resulting duplicating image may then be used in a pressure transfer process by contacting the formed stripped-out image with the surface of a copy sheet, such as ordinary white bond paper, and accordingly applying pressure to' either or both of the back surfaces of the manifold image and/or the copy sheet. The amount of pressure necessary to accomplish the transfer will vary depending upon the many factors involved such as, for example, the particular dye component of the duplicating image, the condition of the tackifred image, the particular binder matrix employed, the delay before placing the duplicating master into a pressure unit, the humidity and temperature of the area in which the transfer step is being carried out, and the like. It has been determined that by using the duplicating image fonned relatively soon after imaging that the pressures will be in the order of about 5 to about 600 pounds and preferably between about to 400 pounds per linear inch of a pressure roller with optimum conditions being about 150- -200 pounds per linear inch. Furthermore, it is to be understood that inasmuch as the binder itself may contain a dye or a pigment to enhance the color of the developed image in either the single phase or two-phase systems, intense coloration of the photoresponsive material itself while generally being desirable is not critical. Therefore, even transparent materials could be used as the photoresponsive ingredient. When desirable, any suitable colorant such as dyes and/or pigments may be added to the photosensitive matrix so as to in- Works and ferric chloride commerciallyavailable from the Fisher Scientific Co. a

The pressure transfer of the resulting duplicating manifold image may be enhanced by tackifying the manifold image thereby increasing its readiness to be transferred when contacted. with the surface of the transfer substrate. This may be accomplished by any suitable means such as by exposure of the developed image to a heat source, by establishing a solvent vapor environment or by including a relatively nonvolatile solvent such as transformer oil in its imaging suspension. lf desirable, such as when an intense colorant is not included in the imaging layer, the color development step may be delayed until the imaging and transfer phases of the process have been completed, in which instance the transferred image would then be contacted with the particular dye and/or pigment. The above-described tackifying steps may also be used with this approach in order to enhance the development of the transferred image.

it may be desirable to employ the manifold image prepared according to the process of the present invention as a spirit duplicating master. ln this case the colorant used to intensify the manifold duplicating image should contain a dyestuff which is soluble in conventional spirit duplicating fluids such as methyl alcohol or ethyl alcohol. Typical dyes are the basic dyestufis rhodamine, crystal violet, malachite green, a diphen' ylmethane dye, commercially available from Victor Chemical Works, nigrosine and induline. Preferably, when used in the present mode of operation, it is desirable to use a colorant such as a Red Pigment N N"-dimethyl-4-methyl-3-phenylazo-3-carboxy-2'-naphthol sulfonamide, which is both photosensitive and also readily soluble in a conventional spirit duplicating liquid. Copies may be reproduced by contacting the duplicating master with a copy sheet in the presence of an alcohol and/or other spirit solvent, such'as water, for example, if a water soluble material is used, which .will pick up a portion of the dye and transfer it to the respective copy sheet. In an alternate approach the manifold image may serve as a resist in the preparation of a hectograph master whereby a commercial hectograph master sheet serves as the receiver sheet in the manifold set and copies are made from the unmasked background areas of the hectograph master according to conventional spirit duplicating procedures.

In still another embodiment of the present invention the manifold image prepared according to the process of the present invention may contain a chemical reactant which when brought into contact with a suitable transfer or copy sheet treated with a complimentary reaction partner for the chemical reactant, in the presence of a spirit solvent, such as tetrahydrofurfuryl alcohol or acetone, will form a reproduction of the image on the transfer sheet. For example, a com pound such as gallic acid, tannic acid, rubeanic acid, hematoxylin, sodium thiocyanate, or any of the conventional color formers may be included in the matrix of the manifold image. Transfer sheets are utilized which are treated with complimentary precipitant metal salts such as iron, vanadium, copper and nickel. Instead of using the color former in the manifold image and the metallic salt in the transfer sheet the ingredients may be reversed with the metallic salt being made a part of the manifold image and the color former apart of the transfer sheet. The transfer or copy sheet may be moistened with the respective material or the particular ingredient may be coated on the copy sheet either by surface coating or by impregnation of the sheet or the pulp from which it is made. When the chemical reactant has not been included in the imaging suspension the resulting image may be made tacky by one of the above-disclosed techniques and the tacky image subsequently developed with a chemically reactive substance and then brought into contact with a transfer sheet containing a suitable reaction partner for the chemical reactant.

The latter spirit duplicating system may be adapted to an azo dye system wherein at least one of a water and alcohol soluble component of an azo dye system is fonnulated to be contained in relatively high concentrations. in the image on the manifold master sheet. The specific system makes use of a diazo compound, preferably in combination with a coupler in the donor coating with which the master is imaged. The copy sheet is brought into surface contact with the image surface of the manifold duplicating master, the master image containing the diazo compound, with or without the coupler. The copy sheet is wetted with a fluid containing a solvent for the diazo and/or coupler andwhich also may contain a material for pH adjustment to enable the coupling reaction to take place to form the dyestuff. When the wetted surface of the copy sheet is brought into contact with the duplicating image of the manifold master sheet, the diazo and coupler are leached for transfer from the imaged master to the copy sheet where reaction takes place in the image areas to form the dyestuff in imagewise configuration. If the image on the manifold master contains the diazo compound by itself or a component thereof, the coupler for the dye formation may be supplied in the spirit fluid or in the cony sheets by way of coating or impregnation. The diazo and coupler used in conjunction with this technique are in themselves substantially free of any color transfer value with the image being realized only upon the combination or interreaction between the two components. Any suitable diazo dye-forming compound may be used in the course of the present invention. Typical diazo compounds are similar to those disclosed in US. Pat. No. 2,838,994 and include such compounds as paradiazo diethyl aniline zinc chloride, paradiazo ethylhydroxy ethylaniline zinc chloride, paradiazo dimethyl aniline zinc chloride, and paradiazo diethyl toluidine zinc salt. As the coupler, use may be made of compounds capable of removal of a hydrogen ion for combination with the chloride ion or otherwise anion of the diazo compound for dye formation. Such compounds include the aromatics in the form of amines, such as aniline, and sub 'stituted anilines, such as dimethyl aniline, phenolic compounds such as phenol, resorcinol, phloroglucinol, 2,3- dihydroxy naphthalene 6-sulfonic acid, phenylmethyl pyrazolone, thio compounds such as thio barbituric acid and cyano compounds such as cyano-acetamide. The diazo dye component and the coupler present together in the imaging material are blocked against the coupling reaction by maintaining control of the pH of the system.

It is advantageous and therefore desirable to enhance the color intensity of the dyes and to thereby improve the quality of the reproduction obtained by treatment of the dyes used in the above spirit systems with an amine base, preferably one that is not too weak nor one that is overly toxic. Typical treatment materials include urea, ethylene diamine, triethanolamine, ammonia, fatty amines, rosin amines, guanidines and amidines, with urea being generally the preferred additive.

DESCRIPTION OF THE DRAWINGS The invention is further illustrated in the following drawings wherein:

FIG. I is a side sectional view of a photosensitive imaging member of the present invention;

FIG. 2 is a side sectional view of an alternate embodiment of the imaging member of the present invention;

FIG. 3 is a side sectional view illustrating exposure and the resulting effect upon the photoresponsive layer of the imaging member of FIG. 2;

FIG. 4 is a side sectional view of the manifold image produced as illustrated in FIG. 3 being utilized as a pressure transfer duplicating master;

FIG. 5 is a diagrammatic perspective view of the manifold image configuration of FIG. 4 with the copy sheet bearing the transferred image partially removed therefrom.

Referring now to FIG. 1 of the drawing, there is seen a supporting donor substrate layer I1 and an imaging layer generally designated 12. In this particular illustration, layer 12 comprises a photoconductive pigment I3 dispersed in a binder matrix 14. Above the imaging layer 12 is applied a third or receiver layer 16. The entire combination will be termed the manifold set. In this particular embodiment of the manifold set, both the donor substrate 11 and the receiver sheet 16 are made up of an electrically conductive material, such as conductive cellophane, with at least one of the supports being on tically transparent to provide for the exposure of layer 12.

Although the structure of FIG. 1 represents one of the simplest forms which the manifold set of the present invention may take, an alternate and preferred embodiment is illustrated in FIG. 2. In this illustration there is shown an insulating donor substrate 21 having coated on its surface a donor, imaging layer generally designated 22. As in FIG. 1 the imaging layer may take any one of the forms described in the discussion supra, however, for purposes of illustration it is shown as consisting of photoconductive pigment particles 23 dispersed in a binder matrix 24. Superimposed upon the imaging layer is a receiving sheet 26. The insulating donor substrate 21 is backed with a conductive electrode layer 25 while the image receiving sheet 26 of the manifold set also consists of an insulating material backed with a conductive electrode layer 27. As mentioned above, either or both of the pairs of layers 21 and 25 and layers 26 and 27 may be transparent so as to permit exposure of imaging layer 22, and are herein represented as such.

FIG. 3 illustrates the effect obtained when the manifold set of FIG. 2 is selectively exposed to radiant energy, represented by lines 29, while under the influence of an electrical field resulting from potential source 30. As a result of the particular properties of the donor composition or matrix the imaging layer fractures along lines subjected to the electromagnetic radiation thereby producing upon separation a manifold image 32 on the surface of receiving substrate 26 while the complimentary or background areas 31 are retained on the donor substrate 21.

In FIG. 4 a copy sheet 41 is superimposed upon the manifold image produced on surface 26 as a result of the exposure system illustrated in FIG. 3 with pressure being applied in a manner demonstrated by pressure roller 42. FIG. 5 illustrates the resulting duplicating effect achieved following the pressure treatment whereby copy sheet 41 is partially turned back or separated from the manifold image 32 and support substrate 26 displaying image 45 on the surface of copy sheet 41 thereby representing the successful image transfer operation.

PREFERRED EMBODIMENTS To further define the specifics of the present invention, the following examples are intended to illustrate and not limit the particulars of the present system. Parts and percentages are by weight unless otherwise indicated. The examples are also intended to illustrate various preferred embodiments of the present invention.

EXAMPLES I-IV A commercial, metal-free phthalocyanine is first purified by acetone extraction to remove organic impurities. Since this extraction step yields the less sensitive beta crystalline form, the desired alpha form is obtained by dissolving grams of the beta form in 600 cc. of sulfuric acid, precipitating it by pouring the solution into 3,000 cc. of ice water and washing with water to neutrality. The thuspurified alpha phthalocyanine is then salt milled for 6 days and desalted by slurrying in distilled water, vacuum filtering, water washing and finally methanol washing until the initial filtrate is clear to produce to form phthalocyanine. After vacuum drying to remove residual methanol, the x-form phthalocyanine thereby produced is used to prepare the imaging layer according to the following procedure: 5 grams of Sunoco 1290, a microcrystalline wax with a melting point of about 178 F. are dissolved in about 100 cc. of reagent grade petroleum ether heated to about 50 C. and quenched by immersing the container in cold water to form small wax crystals. Five grams of the purified and milled BEST AVAILABLE COPY phthalocyanine produced according to the above procedure are then added to the wax paste along with A pint of clean porcelain balls in a 1 pint mill jar. This formulation is then ball milled in the dark for 3% hours at about 70 rpm. and after milling 20 cc. of Sohio Solvent 3440 is added to the paste. This paste is then coated in subdued green light on a 2-mil Mylar sheet with a 012 wire wound draw down rod which produces a coating after drying of about 2.5 microns in thickness. The same paste is applied on three other Mylar sheets with a No. 24 rod to produce a coating thickness of about microns, with a No. 60 rod to produce a coating thickness of about 20 microns and a No. 90 rod to produce a coating thickness of about 43 microns. Each of these coatings is dried in the dark at a temperature of about 140 F. The coated Mylar sheets referred to as the donor substrates are placed on a tin oxide coated NESA glass plate with their coatings facing away from the tin oxide surface of the NESA glass. A receiver sheet of a 2-mil thick Mylar substrate is placed over the coated surface of each donor substrate. Next, a sheet of black, electrically conductive paper is placed over the receiver sheet to form the complete manifold set. The receiver sheet is then lifted up and the phthalocyanine-wax layer activated with one quick brush stroke of a wide camels hair brush saturated with petroleum ether. The receiver sheet is then lowered back down and a roller passed slowly across the closed manifold set with light pressure to remove the excess petroleum ether. The negative terminal of an 8,000 volt DC power supply is then connected to the NESA coating in a series with a 5,500 megohm resistor and the positive terminal is connected tothe black opaque electrode and grounded. With the voltage applied, a white incandescent light image is projected upward through the NESA glass using a WollensakQO-mm, f/4.5 enlarger lens with illumination of approximately l/lOO foot-candle applied for 5 seconds for a total incident energy of about 0.05 foot-candleseconds. Following exposure, the receiver sheet is peeled from the set with the potential source still connected. The small amount of petroleum ether present evaporates within a short period of time yielding a pair of excellent quality images with a duplicate of the original on the donor sheet and a reverse of the original on the receiver sheet. All four coating thicknesses produced good quality images. In each instance the resulting manifold image is contacted with the surface of a paper copy sheet under a pressure of about 200 pounds per linear inch thereby transferring a reproduction of the image to the surface of the respective copy sheet. By repeating the contacting process multiple transfers of the manifold image are produced. As the thickness of the phthalocyanine-wax imaging coating is increased, the number of copies which are obtained from the duplicating manifold image are also increased.

EXAMPLES V-Vlll The procedures of Examples I-IV are repeated with the exception that a tri-mix consisting of 5 parts of the metal-free phthalocyanine of the above examples, 2 parts magenta pigment, Watchung Red B, l-(4-methyl-5'-chloroazobenzene- 2'-sulfonic acid)- 2-hydroxy-3-naphthoic acid, C.I. No. 15865, commercially available from El. dulont de Nemours and a yellow pigment, Algol Yellow GC, l,2,5,6 (Ii-(QC- diphenyl)-thiazoIe-anthraquinone, C.I. No. 67300, available from General Dyestuffs is utilized in each instance as the imaging suspension. In each case a pressure of 400 pounds per linear inch is used during the transfer step to obtain reproduction prints of the original.

EXAMPLES IX-XII Five donor substrates. are coated according to the procedure of Example I except thatthe ratio of phthalocyanine pigment to wax is 5 to l in Example IX, 1 to 4 in Example X, l to 5 in Example XI, and l to in Example XII. When these donors are imaged according to the procedure of Example I, all produce dense high-resolution images with the exception of Example XII which produces a coating of lower reflection density and somewhat lower resolutions. However, with Example XII as well as Examples IX through XI duplicate images were obtained when contacted with a copy sheet under pressure as in Example I.

EXAMPLES XIII-XVII The procedure of Example I is repeated except that. the phthalocyanine pigment is mixed at a ratio of I to l per each of the following binders: for Example XIII, Sunoco microcystalline wax grade 5825 having an ASTM-D-l27 melting point of about 151 F. is used; for Example XIV, grade 985, another Sunoco microcrystalline wax having a melting point of 193 F. is used; for Example XV, Sunoco paraffin wax, grade 5512 having a melting point of 153 F. (ASTM-D-87) is used; for Example XVI a low molecular weight polyethylene commercially available from the Eastman Chemical Products, Inc. under the trade name Epolene C-I2 having an approximate molecular weight of 3700, a ring and ball softening point of 92 C., an acid number of 0.05 and a density at 25 C. of about 0.893 is used; for Example XVII grade N-II of the Epolene low molecular weight polyethylene series is employed having an approximate molecular weight of L500, a ring and ball softening point of 170 C., a density at 25 C. of about 0.924 and an acid number of 0.05 To this mixture in each instance is added a crystal violet dye in amounts of one part dye to one part of the combined pigment and binder. Each of these coatings is imaged according to the procedure of Example I and all are found to produce good. quality images. Each manifold image produced is contacted with the surface of a paper copy sheet in the presence of a methanol solution thereby producing in each case duplicates of the manifold image.

EXAMPLES XVIII-XXII Five donors are prepared and imaged according to the procedure of Example I with the exception that the following activators are used in each of the examples: Example XVIII is activated with Sohio Odorless Solvent 3440; Example XIV is activated with carbon tetrachloride; Example XV is activated with Freon 214 (tetrachlorotetrafluoropropane); Example XVI is activated with Dow-Coming silicone oil, DC 200 (dimethylpolysiloxane); and Example XVII is activated with Wemco-C transformer oil, a high boiling point, long chain aliphatic oil commercially available from Westinghouse Electric. In each Example there is added to the pigment-binder composition 2 parts rubeanic acid per parts of the pigment binder composition. Each of the resulting manifold images is contacted with a transfer copy sheet which has been impregnated with nickel sulfate hexahydrate in the presence of a tetrahydrofurfuryl alcohol solution to produce an image reproduction. The process is repeated several times to illustrate the duplicating qualities of the manifold masters.

EXAMPLES XXlII--XXVIII In Examples XXIII-XXVII six donors are made and imaged according to the procedure of Example I with the exception that the pigment used forming the imaging layer is as follows: in Example XXIII the stabilized alpha crystalline form of metal-free phthalocyanine is employed. This material is prepared by acetone extraction of the commercial metal-free phthalocyanine, and sulfuric acid solution reprecipitation of the extracted material as explained in Example I followed by milling for one day in a porcelain mill. This milling stabilizes the alpha form from conversion to the beta form. In Example XXIV the beta form of metal-free phthalocyanine is used. This is produced by the same acetone extraction and precipitation from sulfuric acid solution with no milling. In Example XXV, Algol Yellow GC Color Index No. 67300 (l,2,5,6-di (C,C'- diphenyl)-thiazoIe-anthraquinone is used, In Example XXVI the pigment used is 2.9-dimethylquinacridone. In Examplev XXVII, French process zinc oxide is used as the pigment. In

Example XXIV mercuric sulfide is used as the ni I the binder-pigment matrix of each one of the donors is included one part paradiazodiethylaniline zinc chloride per 100 parts of the pigment binder matrix. The resulting manifold images are contacted respectively with paper copy sheets which are coated with a material containing dimethyl aniline in the presence of a spirit solution containing 1 part propylene glycol, three pans methanol, and percent water by weight. The resulting images produced due to the present system further illustrate the use of the manifold images of the present invention as duplicating masters.

EXAMPLES XXIX-XXX" Four imaging members or manifold sets are made up and imaged according to the procedure of Example I with the exceptions as to various electrodes, donor substrates and receivers as follows:

These modifications are intended to be encompassed within the scope of this invention.

We claim:

1. A method which comprises:

a. selectively exposing at least one surface of a manifold set to actinic radiation, while said set is subjected to an electric field; said surface being transparent to said radiation, said manifold set comprising a frangible electrically photosensitive imaging layer interpositioned between a donor substrate and a receiver sheet;

b. separating said receiver sheet from said donor substrate, thereby fracturing said imaging layer, said receiver sheet having adhered to its surface in imagewise configuration an image of said electrically photosensitive imaging layer and said donor substrate having adhered to its surface an image complimentary to that on the receiver sheet;

Base electrode Donor substrate Receiver sheet Upper electrode Exampge No.:

X IX Cellophanem. Electrode Electrode Cellophane.

do My1ar. 0........ Do.

NESA glass... Cellulose acetate. Cellulose acetate Conductive black paper. d0 Mylar Electrode Aluminum.

The manifold images produced according to these examples EXAMPLE XXXlll Utilizing the imaging suspension prepared as in Example I a manifold set is fabricated and exposure carried out thereby producing upon separation a pair of high quality images, with a duplicate of the original on the donor sheet and a reverse of the original on the receiver sheet. The imaged receiver sheet surface is then contacted under a pressure of about 200 pounds per linear inch with the surface of a conventional crystal violet Ditto hectographic master to produce the resisttype printing master discussed above. The master is placed on the drum of a hectograph copy duplicator machine and prints produced thereby demonstrating the operability of the resisttype master produced.

EXAMPLE XXXIV The imaging process of Example l is repeated except that a crystal violet Ditto master is used as the receiver sheet. The remainder of the process is the same with the image formed on the surface of the receiver sheet serving as a masking material to produce a resist-type hectograph master sheet as in Example XXXlll. The resulting images obtained are similar in quality to those produced by the master prepared according to the procedure of Example XXXlll.

Although the present examples were specific in terms of conditions and materials used, any of the above-listed typical materials may be substituted when suitable in the above examples with similar results. In addition to the steps used to prepare the manifold printing master of the present invention, other steps or modifications may be used, if desirable. For example, the image produced on the donor support or as a result of transfer from the manifold image may itself be used as the duplicating master. in additiomother materials may be inc porated in the photosensitive material, binder, donor sheet, receiver sheet or transfer sheet which will enhance, synergize or otherwise desirably effect the properties of these materials for their present use. For example, increased image durability and hardness may be achieved by treatment with an image material hardening agent or with a hard polymer solution which will wet the image material but not the substrate.

Anyone skilled in the art will have other modifications occur to him based on the teachings of the present invention.

c. contacting the image residing on at least one of said receiver sheet and said donor substrate under pressure with a copy sheet so as to transfer a portion of said image to said copy sheet; and

d. repeating said contacting step until the desired number of copies are produced.

2. The process as described in claim 1 including the step of heat treating the image so as to render it tacky prior to said pressure transfer step.

3. The method of claim 1 including the step of rendering said imaging layer frangible by the application thereto of an activator.

4. The method of claim 1 wherein the electrically photosensitive imaging layer comprises an electrically photosensitive material dispersed in a binder.

S. The method of claim 4 wherein the electrically photosensitive material is an organic material.

6. The method of claim 1 wherein the electric field is in the range of from about 1,000 to about 2,500 volts per mil.

7. A method which comprises:

a. selectively exposing at least one surface of a manifold set to actinic radiation, while said set is subjected to an electric field, said surface being transparent to said radiation, said set comprising a frangible electrically photosensitive imaging layer interpositioned between a donor substrate and a receiver sheet, said imaging layer containing therein a colorant soluble in a spirit solvent;

b. separating said receiver sheet from said donor substrate, thereby fracturing said imaging layer, said receiver sheet having adhered to its surface in imagcwise configuration an image of said imaging layer and said donor substrate having adhered to its surface an image complimentary to that on the receiver sheet;

c. contacting the image residing on at least one of said receiver sheet and said donor substrate with the surface of a copy sheet in the presence of a spirit solvent thereby transferring an imprint of the manifold image to the surface of said copy sheet; and

d. repeating step (0) until the desired number of copies are reproduced.

8. The method of claim 7 wherein the spirit solvent is selected from the group consisting of alcohol and water.

9. The method of claim 7 including the step of rendering said imaging layer frangible by the application thereto of an activator.

10. A method which comprises:

a. selectively exposing at least one surface of a manifold set to actinic radiation, while said set is subjected to an electric field, said surface being transparent to said radiation, 11. The process as described in claim 10 wherein said color said set comprising a frangible electrically photosensitive producing reagent is a diazo compound and said complimenimaging layer interpositioned between a donor substrate tary reaction partner is a coupling reactant.

and a receiver sheet, said photoresponsive composition 12. Amethod which comprises:

containing therein a color producing reagent capable of 5 a. selectively exposing at least one surface of a manifold set producing color upon reacting with a complementary reaction partner;

. separating said receiver sheet from said donor substrate,

thereby fracturing said imaging layer, said receiver sheet to actinic radiation, while said set is subjected to an electric field, said surface being transparent to said radiation, said set comprising a frangible electrically photosensitive imaging layer interpositioned between a donor substrate h vi dh r d to i surface i imagewise configu ation l0 and a receiver sheet, said receiver sheet having contained an image of said imaging layer and said donor substrate there!" I f Soluble In a P b having adhered to its surface an image complimentary to Separatmg f f' from 531d fionof :Wbslfale, h on h receiver h thereby fracturing said imaging layer, said receiver sheet contacting in the presence of a spirit solvent the image hfwmg fldhel'ed surface In lmagewlse configuraresiding on at least one of said receiver sheet and donor an l p q W 'i substrate with the surface of a copy sheet treated with 'comactmg Sald recelvefheet bearing 531d g? with the said complimentary reaction partner for said color of a P Sheet m the presfence f a l Solvent producing reagent such that a portion of said color for sald colorant thereby imnsfenlng an l p from the producing reagent reacts with Said cbmplimemary reac unmasked background areas of said receiver sheet to the tion partner to produce a visible image on said copy Surfac? ofsad copy shFeti and Sheet; and repeating step (c) until the desired number of copies are repeating step (c) until the desired number of copies are Producedproduced. 

